It was billed as a joint venture between two cinematic superpowers, a collaboration between east and west. But the comic-book blockbuster Iron Man 3 has now been split into two distinct entities. The version playing to audiences in China will contain Chinese characters and Chinese sequences. The official international version, by and large, will not.

The change has not gone unobserved by some film fans in China, with a handful of bloggers crying foul over locally-shot scenes that failed to find their way into the version released to the rest of the world.

Disney-owned Marvel Studios announced in March that the version playing to audiences in China would contain Chinese superstars such as Wang Xueqi and Fan Bingbing, as well as sequences shot in China. Yet some are still angered. Weibo user shiahsu516 wrote that Wang's role seemed "unnecessary" and said the Chinese trailer was "misleading". Another microblogger, UK-based Mr Stones P, described Wang's turn as "the walk-on of all walk-ons". Separately, Chinese bloggers and newspapers have noted that sequences shot in Beijing in December, including one in which Iron Man takes off into the sky in front of Dr Wu and a group of cheering schoolchildren at the famous Yongdingmen Gate, are completely missing. Also gone is a segue in which Mr Wu tries to contact Tony Stark on the phone.

Wang, whose previous credits include Yellow Earth and Reign of Assassins, told the Hollywood Reporter that he had accepted the role on the understanding that Dr Wu would be a major figure in the drama. "I said to this person contacting me: 'It wouldn't do if it was a character who's finished off after a few fights,'" he recalled. "I was then assured that, 'No, you're going to be the man who saves his [Iron Man's] life."

Wang went on to describe the character as "a very complicated individual" and the role as "very challenging". But the international version of Iron Man 3 reportedly restricts Wang's appearance to a 10-second sequence in the opening scene, plus a fleeting glimpse towards the end of the film where his face is obscured by a mask.

Iron Man 3 was conceived and developed as a collaboration between Marvel Pictures and DMG Entertainment. Director Shane Black explained that the film's producers required some scenes to be shot in China, but admitted that neither he nor the film's star, Robert Downey Jr, had shot them. "I was told they wanted additional content for China," Black said. "It was sort of an experiment and I was very interested by it … I looked at the scenes to sort of approve them."

The decision to release two versions of Iron Man 3 has already prompted condemnation from bloggers and critics in China. Zhang Pimin, deputy chief of the State Administration of Radio, Film and Television recently criticised what he described as "fake" co-productions that did not contain enough bespoke Chinese content.